Creating multiple region

niazaliahmed · July 22, 2010, 09:53

How to create a geometry which has two regions?

nomad · July 23, 2010, 13:03

You should expound on that question so that someone can actually help you.

MartiJ · August 11, 2010, 12:01

I have a question about boundaries and using them to create regions.

Do I need complete set of boundaries to create a new region inside an existing one?
I mean, do the boundaries have to set up a closed volume (cube, sphere, some abstract volume etc.)?

Thanks in advance!

sreenivas · August 16, 2010, 05:00

You need not close the boundaries in single region but all the regions should be closed to make it a complete closed volume

MartiJ · August 16, 2010, 05:15

Okay,

but I don't have the regions next to each other.

Imagine the case when you have a cylindrical region inside a bigger pool (cube or whatever). I need to define that this cylinder is e.g porous.

So, question is: is it possible to describe/define/constrain this cylindrical porous region by, lets say, selecting only the side surface of the cylinder and not the bottom and top surfaces. So it is just open-ended (like a pipe). Will this procedure give me a new region or do I need to use/have the top and bottom surface too, to create a cylindrical region inside a bigger one..

Bit confusing, but I need to get things clear..

BR.

sreenivas · August 16, 2010, 05:50

STAR still will treat this as the valid region but porous representation of cylinder is not valid until you select remainig surfaces.The best thing is to do two diffrent volume meshes and create an interface between these two.

MartiJ · August 16, 2010, 06:11

Oh, I see.

One thing, I need to use the existing mesh (can't mesh again any region).

Other thing, I have only the mesh (not the geometry parts) and a number of boundaries pre-defined in it (I just can ask mesh creators to add some boundaries into the mesh).

So, if I really need to define an inner region with different properties, then I need to have boundaries closing this region (cylinder side, top and bottom surfaces e.g.) ?

EWeird thing is, every time I define a region like just by selecting, for example, two boundaries, after saving and reopening the model, this defined region is cut out from rest of the region and it is impossible to plot it anymore (just can not see it, gone). Why?

Anto · September 22, 2010, 11:59

I think you should create different regions (I mean one for the porous medium and other regions for the remaining fluid cells). All the regions must be closed. you have to "convert to interface" (right clicking on them) the surfaces that limit the porous medium . automatically a copy of the interfaces created will be produced. these interfaces must be part of the region containing the porous medium and of the region surrounding.

As far as the visualization problem, you have to create a new mesh scene and in this scene you will be able to see all your model!

July 22, 2010, 09:53	Creating multiple region	#1
niazaliahmed New Member Niaz Ali Ahmed Join Date: Jun 2010 Posts: 14 Rep Power: 15	How to create a geometry which has two regions?

August 11, 2010, 12:01		#3
MartiJ New Member Marti J Join Date: Jul 2010 Location: swe Posts: 14 Rep Power: 15	I have a question about boundaries and using them to create regions. Do I need complete set of boundaries to create a new region inside an existing one? I mean, do the boundaries have to set up a closed volume (cube, sphere, some abstract volume etc.)? Thanks in advance! Last edited by MartiJ; August 15, 2010 at 09:33.

August 16, 2010, 05:00	Hi	#4
sreenivas New Member sreenivas Join Date: Jul 2010 Posts: 23 Rep Power: 15	You need not close the boundaries in single region but all the regions should be closed to make it a complete closed volume

August 16, 2010, 05:50	Hi	#6
sreenivas New Member sreenivas Join Date: Jul 2010 Posts: 23 Rep Power: 15	STAR still will treat this as the valid region but porous representation of cylinder is not valid until you select remainig surfaces.The best thing is to do two diffrent volume meshes and create an interface between these two.

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July 23, 2010, 13:03		#2
nomad Member John Join Date: Aug 2009 Posts: 92 Rep Power: 16	You should expound on that question so that someone can actually help you.

August 16, 2010, 05:15		#5
MartiJ New Member Marti J Join Date: Jul 2010 Location: swe Posts: 14 Rep Power: 15	Okay, but I don't have the regions next to each other. Imagine the case when you have a cylindrical region inside a bigger pool (cube or whatever). I need to define that this cylinder is e.g porous. So, question is: is it possible to describe/define/constrain this cylindrical porous region by, lets say, selecting only the side surface of the cylinder and not the bottom and top surfaces. So it is just open-ended (like a pipe). Will this procedure give me a new region or do I need to use/have the top and bottom surface too, to create a cylindrical region inside a bigger one.. Bit confusing, but I need to get things clear.. BR.

August 16, 2010, 06:11		#7
MartiJ New Member Marti J Join Date: Jul 2010 Location: swe Posts: 14 Rep Power: 15	Oh, I see. One thing, I need to use the existing mesh (can't mesh again any region). Other thing, I have only the mesh (not the geometry parts) and a number of boundaries pre-defined in it (I just can ask mesh creators to add some boundaries into the mesh). So, if I really need to define an inner region with different properties, then I need to have boundaries closing this region (cylinder side, top and bottom surfaces e.g.) ? EWeird thing is, every time I define a region like just by selecting, for example, two boundaries, after saving and reopening the model, this defined region is cut out from rest of the region and it is impossible to plot it anymore (just can not see it, gone). Why?

September 22, 2010, 11:59		#8
Anto New Member Join Date: Jan 2010 Posts: 2 Rep Power: 0	I think you should create different regions (I mean one for the porous medium and other regions for the remaining fluid cells). All the regions must be closed. you have to "convert to interface" (right clicking on them) the surfaces that limit the porous medium . automatically a copy of the interfaces created will be produced. these interfaces must be part of the region containing the porous medium and of the region surrounding. As far as the visualization problem, you have to create a new mesh scene and in this scene you will be able to see all your model!